This invention relates generally to electrical current conduction in solid state materials, and more particularly relates to techniques for manipulating the mobility of free electrical charge carriers, for controllably increasing or decreasing electrical current conduction in solid state materials.
Electrical current conduction in a solid state material such as a semiconducting material is by free electrical charge carriers, holes and electrons, which are either intrinsic to the material or are donated to the material. Charge carriers can be donated to a solid state material by, e.g., adding impurity atoms the material, by the process of doping. The number of free carriers in the matrix of a host material can then be controlled by the concentration of the impurity atoms. Whether the free electrical charge carriers are intrinsic or donated to a material, the electrical conductivity of the material is proportional to the product of the electrical charge carrier concentration and the mobility of the electrical charge carriers. Carrier mobility characterizes how fast an electrical charge carrier can move through a solid state material, and depends on the number of scattering centers present in the solid state material as well as the interaction potential of those scattering centers with the electrical charge carriers.
Charge carrier mobility is an important characteristic for a wide range of solid state materials, and particularly for solid state semiconducting materials. Increased charge carrier mobility is for many applications desired for enabling an increase in electrical conductivity in semiconductor devices. The achievement of increased charge carrier mobility, and indeed the controlled manipulation of charge carrier mobility in general, provides improved semiconductor device performance and enables a wide range of semiconductor devices and systems.